Electronic devices may be damaged when dropped by accident, more particularly, electronic devices having four corners may be seriously damaged. Protection blocks may be attached to the corners of the electronic devices to protect the electronic devices. The protection blocks are attached to the corners of the electronic device by adhesion. A pressing device is employed to attach the protection blocks to the electronic device. The pressing device includes a knob, a linking assembly, a pressing assembly and a seat. An end of the linking assembly is pivotally connected to the seat, the pressing assembly is connected to an end of the linking assembly opposite to the seat and is located above the seat. When the knob is pressed under a predetermined force, the pressing assembly is moved downward with the linking assembly, thus pressing the plurality of protection blocks. Because the knob is connected to the linking assembly, and the linking assembly is pivotally connected to the pressing assembly, when the protection blocks exert a counter-force on the pressing assembly, gaps may be generated between the knob, the linking assembly, and the pressing assembly. Such that, the gaps may deform to absorb the force, so the pressing assembly may not properly or sufficiently contact the protection blocks to the corners of the electronic device, thereby a pressing quality of the pressing device is reduced.